How to conduct a valid experiment in a middle school science class.

1. Experimental Design How to conduct a valid experiment.

14. Here are some different examples:

15. Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

16. Identify the variables in this investigation!

20. Another example:

21. An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

22. What are the variables in this investigation?

26. Here’s another:

27. The temperature of water was measured at different depths of a pond.

29. Last one:

30. Students modified paper airplanes by cutting pieces off, adding tape, or adding paper clips to increase the distance thrown.

32. Now let’s take what we know about these variables and use them in an experiment!

35. Are there any questions?!